(a) Field of the Invention
The present invention relates to an apparatus and method for allocating a resource in multi-beam satellite communication, and an apparatus and method for selecting an active beam and allocating a bandwidth resource in multi-beam satellite communication on the assumption that power flux density of each beam stays constant.
(b) Description of the Related Art
In satellite communication systems, a wave radiated from a satellite to the ground surface is referred to as a beam, and the ground surface irradiated by the beam is referred to as a cell. The satellite communication systems include a single beam satellite communication system in which a satellite uses a single beam, and a multi-beam satellite communication system in which two or more different spot beams are used.
In the multi-beam satellite communication system, a service area is divided into a plurality of cells, and a mobile terminal forms a communication link with a satellite through a beam corresponding to the user, and receives a service through the communication link.
In the multi-beam satellite communication, as dynamic allocation of limited satellite resources such as power, bandwidth, or spot beams is enabled in consideration of traffic demand and channel status of each spot beam, the overall system capacity is expected to grow by a flexible system configuration.
Currently, the International Telecommunication Union (ITU) specifies and regulates power flux density (PFD) levels of signals transmitted from a satellite to the ground to limit interference effects that may be exerted on adjacent spot beams or other ground reception and communication facilities, which is a requirement that is necessarily taken into account in the design of a satellite communication system.
To solve the problem of a large variation width in interference level between adjacent beams that may occur in a dynamic resource allocation scheme for a multi-beam satellite system, there is a need for a method that is capable of maximizing the utilization of limited satellite resources to increase overall system capacity on the assumption that PFD stays constant to keep the interference level of each spot beam at a fixed level.